Si对Hastelloy N合金氧化行为的影响

Effects of silicon on the oxidation behavior of Hastelloy N superalloy at 850℃

摘要:

利用不连续增重法,研究了不同Si含量的Hastelloy N合金850℃恒温氧化行为。结果表明随Si含量的增加,氧化动力学曲线保持抛物线规律。氧化100h后,氧化膜出现分层现象,最外层均为NiO、NiFe₂O₄等复合氧化物,中间层为Cr₂O₃、MoO₂等氧化物。由于在氧化层与基体界面处形成连续致密的SiO₂层,有效阻止Cr离子向外扩散进入氧化层,促进Hastelloy N合金中间层形成较为致密的Cr₂O₃氧化层,提高了合金的抗氧化性能。

Abstract:

The isothermal oxidation behavior of Hastelloy N superalloy with different silicon contents in air at 850℃ were investigated by using discontinuous increasing weight method. The results showed that oxidation mass gain kinetics of the samples follow the parabolic law. It was observed that the surfaces of the alloys exhibited a multi-layer structure after 100h oxidation. The outer oxide flim of Hastelloy N superalloy mainly consists of NiO, NiFe₂O₄and other oxide composites. The middle layer is confirmed to be Cr₂O₃ and MoO₂. Since a continuous and dense SiO₂ sublayer is formed at the metal-oxide interface, it is effective to prevent Cr diffusion. The addition of Si promotes the formation of a relatively continuous and compact Cr₂O₃ and it can strongly improve the oxidation resistance.